The Ford Barn

gearheadbill · 12-05-2017, 08:38 PM

Can anyone tell me how to check that my temp sender works or not? Not wanting to check accuracy; just whether it's working. Temp gauge is not wired up as yet. Thanks.

tubman · 12-05-2017, 09:15 PM

That looks a lot like the sender in my '51 and I think they are the same. You can do a preliminary test with a multimeter. I had 4 senders; three good ones and one bad one. The three good ones "ohmed out" at 13-14 ohms, while the bad one had zero resistance (0 ohms). This is not a definitive test, but about as easy as you can get. If you do a search, there are some threads on this forum that discuss this in detail including a couple of more comprehensive tests.

BTW, Reproduction senders are notoriously unreliable, while NOS ones are very hard to find. I have found that these can be repaired. The only problem is that the repair can sometimes be detected by a close inspection of the crimps holding the device together.

BillM · 12-05-2017, 10:27 PM

Connect the terminal on the sender to one terminal of the gauge and the other terminal of the gauge to 6 volts; ground the body of the sender. Polarity doesn't matter for a test. Temperature gauge will go from Hot to Cold when power is on with the sender in the circuit. As the sender is heated up the points inside it momentarily open and the gauge starts to go back to Hot. If you have a test light you could wire it in series with the sender and see it blink off briefly as current flows through the circuit.

gearheadbill · 12-06-2017, 03:39 PM

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tubman: Thanks! exactly the info I need.

BillM: Thanks as well. Since I have no idea whether the currently non-wired-up gauge works or not (it was not wired up when I got the car...can't even find a wire for in the engine bay), everything is suspect and I will put your advice to use as well!

12-05-2017, 09:15 PM	#2
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,303	Re: 1940 temp sender test? That looks a lot like the sender in my '51 and I think they are the same. You can do a preliminary test with a multimeter. I had 4 senders; three good ones and one bad one. The three good ones "ohmed out" at 13-14 ohms, while the bad one had zero resistance (0 ohms). This is not a definitive test, but about as easy as you can get. If you do a search, there are some threads on this forum that discuss this in detail including a couple of more comprehensive tests. BTW, Reproduction senders are notoriously unreliable, while NOS ones are very hard to find. I have found that these can be repaired. The only problem is that the repair can sometimes be detected by a close inspection of the crimps holding the device together.

12-05-2017, 10:27 PM	#3
BillM Senior Member Join Date: May 2010 Location: Everett, WA Posts: 504	Re: 1940 temp sender test? Connect the terminal on the sender to one terminal of the gauge and the other terminal of the gauge to 6 volts; ground the body of the sender. Polarity doesn't matter for a test. Temperature gauge will go from Hot to Cold when power is on with the sender in the circuit. As the sender is heated up the points inside it momentarily open and the gauge starts to go back to Hot. If you have a test light you could wire it in series with the sender and see it blink off briefly as current flows through the circuit. __________________ My web page: http://myplace.frontier.com/~wgmumaw/

12-06-2017, 03:39 PM	#4
gearheadbill Senior Member Join Date: May 2010 Location: Snohomish, WA Posts: 401	Re: 1940 temp sender test? Sponsored Links (Register now to hide all advertisements) tubman: Thanks! exactly the info I need. BillM: Thanks as well. Since I have no idea whether the currently non-wired-up gauge works or not (it was not wired up when I got the car...can't even find a wire for in the engine bay), everything is suspect and I will put your advice to use as well!